Suburban Wild: Animal adaptations respond to humans’ noise

The world isn’t only getting warmer, it’s getting louder. Increase in human population and industry has raised Earth’s noise volume down the ages, and the evolution of many species is being affected. Sound was there before life emerged on Earth: waves lapping, ice cracking and wind whistling through canyons. The physiology of the first life forms would have been shaped by vibrating geo-sound, while current species must adapt to human-generated sound.

Animals evolve to fit not only a food niche but also the niche where they can hear prey, predators and mates. The world of human-caused sound distorts this. City noise, for instance, changes birdsong. It has become louder, as have whale vocalizations in the presence of underwater shipping noise.

Bioacoustics is the study of the living sound-scape, and the sounds created by living things are termed “biophony.” Nature is a symphony, but its music is more jazz than classical for it constantly improvises, altering the sound-scape. The orchestra is often drowned out by humanity.

Anything murmuring or susurrating is overwhelmed in cities, which since 2008 are the homes of over half of Earth’s human population. The natural sounds we can still hear locally include caws of crows, shrieks of gulls, barks of dogs, and if we’re enjoying a relatively quiet zone maybe robins at dusk or raccoons chortling under a hedge. We rarely hear the whir of insect wings, the click of cricket legs, croaking of frogs, rustling of leaves or the barking of sea lions offshore.

These sounds are overlaid by sirens, loudspeakers, chainsaws, jackhammers, leaf blowers and aircraft, and indoors by the cackle of media, appliances and air conditioning. Even outside cities, the wilderness is ringing with the cacophony of snowmobiles, ATVs, helicoptors, logging trucks and whining wind turbines, all of which fragment biophony. Wild creatures must feel they are going insane, but the results of noise pollution harm humans as well, for according to the World Health Organization and various university studies, depression, high blood pressure, insomnia, ADHD and rage result from noise. Recorded effects of noise on schoolchildren include a decrease in achievement and IQ scores.In 1862 an editorial in the Colonist deplored “the gradual diminution of trees great and small” along the northern side of Beacon Hill Park, and opined that “what has taken a century to mature would never be suffered to be whittled down …” The writer could also have championed the trees in Oak Bay, which back then was a delectable retreat from commerce, noise and what the Colonist called “the smell of the shop.”

Trees are still our best ally in preserving pockets of quiet. Along boulevards and when densely planted they buffer noise as much as pollution. They also reduce atmospheric warming by cooling concrete “heat islands” with their shade, and they give wildlife a place to hide and build nests. What would our herons, crows, robins, chickadees, woodpeckers, wrens, jays, bats, raccoons and squirrels do without them? For them, both heat and noise are scaled back in winter. Maybe during these long nights the deer and raccoons will come upon a midnight clear among the trees, and enjoy a little peace and goodwill.

In a Japanese healing modality called “forest bathing,” people too escape harmful noise by retreating to the woods. But how close, for us, are the woods? Here is one rationale for preserving heritage gardens and parks within cities. We call this green-space, but it is also green-quiet. Making space for biophony doesn’t only protect wildlife, it enhances human health as well.

Barbara Julian is a local writer and nature enthusiast. She writes monthly about the many creatures making their home in and around Oak Bay.